With their increasing popularity, phase-field models have also been applied to hydraulic fracturing by extending the Francfort–Marigo energy functional to poroelastic media. However, when hydraulic fractures propagate in the so-called viscous-dominated regime, where surface energy dissipation is negligible compared to fluid viscous dissipation, existing phase-field models can become unstable and often lead to non-localized phase-field (damage) profiles. In this work, we propose a micro-poroelasticity-based phase-field fracture model to overcome the issues of non-localized damage and pore-pressure profiles. The proposed model enables a variationally consistent formulation and a rational derivation of effective stress and phase-field-dependent poroelasticity. A modified fixed-stress split scheme is employed to solve the hydromechanical coupling problem. We verify the model against standard microporosity problems, mechanically induced fracture, and viscous-dominated hydraulic fracturing. We then demonstrate the interactions between fluid flow and poroelasticity and their respective contributions to fracture propagation.